In reply to Nicola:
OK, grades 2 and 3, fitting your other criteria:
Piz da Cir V - grade 2, above Corvara on Passo Gardena. Easy access from the road via ski lift, out and back, easy, popular, good views from the top.
Ivano Dibona - grade 2, Take the lifts up to Cristallo from near Cortina, walk as far along as you feel comfy with, then turn round. Longest foot suspension bridge in the Dolomites right at the start. Best to do this later, when you're acclimatised to the altitude, because it's up at 3,000 metres.
Brigata Tridentina - grade 3, but low in the grade. Above Corvara on Passo Gardena. VERY popular, huge car park, have lunch in the rifugio at the top. Descent path is well trodden, but a bit brutal on the knees. Consider hiking poles.
Laguzoi Tunnels - only grade 1 (I'd happily do it without a VF kit, tbh), but really cool and interesting. Approach via cable car from Passo Falzarago, descend on foot through the VF tunnels.
Averau - grade 2, near the summit of Passo Falzarago coming up from Cortina. Decent access from the road via chair lift, easier access via another chairlift if you want to do a bit more driving. Lots of fun. Do it in good weather for a walk to the summit (routefinding hard in clouds) for a *stunning* view of Cortina and the Tofana group.
If you want to try a slightly more challenging grade 3, Col Dei Bos (AKA Degli Alpini). Goes up a lesser summit of Mount Laguzoi. Start is high in the grade for a 3, but the hardest part is at the beginning. Lovely descebr round to the left from the top (don't be tempted to take the quick way down to the right - it's grotty), the latter bit of which meets up with descent from Laguzoi Tunnels.
That should be plenty to be getting on with. If your friends end up happy on 3s, you might want to consider Trincee as a finalé. It's a 4, but it's easilly escapable and spectacular.